Here's a bit of an odd thought for the day: It first happened with Bluetooth not so long ago: With its data rate limited to 2-3 MBit/s, Bluetooth is no longer capable of forwarding data between let's say a PC and a phone at full HSDPA speeds offered today in networks. As reported here, I get more than 5 MBit/s with a HSDPA category 8 device in a live network.
With the most popular Wi-Fi variant currently used, i.e. 802.11g with a raw data rate of 54 MBit/s and a practical maximum throughput of around 20 MBit/s, similar things will happen once we go to HSPA+ with data rates of 21 and 28 MBit/s and beyond.
Sure there's 802.11n that is capable of much more but it requires several antennas and its unlikely that we'll see it in mobile devices with several antennas anytime soon. But then, the thought is mainly academical anyway these days. While I used to tether my PC and mobile phone quite a lot in the past I only resort to it seldomly these days. In most countries, an extra (prepaid) SIM card for the PC for wireless broadband has become so affordable that I'd rather spend a bit more money than to go through the hassle of tethering.
But still, the thought shows nicely how technology has progressed over the past few years, with a wide area network technology now at the brink of surpassing the speed of a short range wireless technology that was only a couple of years ago thought of as being super fast.
Hi Martin, sorry but I disagree quite a bit with most of your assumptions 🙂
1) As you explained yourself in the past, the gap between peak and realistic throughput in the vast majority of cases increases further with 64QAM/MIMO. So I don’t see happening at 21Mbps, and not badly so before 42Mbps – if that’s with dual carrier instead of MIMO, I agree it could be quite dramatic though.
2) 802.11n *is* coming to smartphones. Just Google Broadcom BCM4329, CSR UF6026, or Atheros AR6003. The first two are 72Mbps (1 antenna 20MHz) and the last 150Mbps (40MHz). However, MIMO is coming too: CSR for example put it as part of their 40nm roadmap. So that’s 300Mbps (2-3x LTE!) although for power/cost reasons only on the receive side which is still 1 antenna/150Mbps (same reasoning as LTE). Btw, 11n average-to-peak perf actually improves so 72Mbps should be plenty even for 42Mbps IMO.
2) 2 Antennas could be worse, and there are tricks to get away with only a single physical one(google Skycross)
Cheers.
3)
Hi there,
Thanks for the comment and the details on the upcoming Wi-Fi chipsets.
802.11n also uses 64QAM and MIMO, so peak rates here just depend as much on the channel conditions than HSPA.
But then, the post is intended to show how far HSPA data rates have been pushed in the past couple of years. Once upon a time it never entered my mind that one day, HSPA could surpass today’s 802.11g speeds. That’s the message of the post 🙂
Cheers,
Martin
Hi Martin, first sorry for the awful formatting on the previous post, although you’ll hopefully forgive me if I tell you it was written on an iPhone 😉 And thanks for the reply!
I obviously agree with most of what you said. It’s clear that 3.9G/4G would get to that point, but it was also a surprise to me, and I assume many others, that WCDMA got this far.
A few noteworthy nitpicks though:
1) WiFi signals are likely to be better than HSPA ones on average because of the shorter range, and MIMO is likely to work better in a more indoor-centric environment.
2) I could be horribly wrong as I have no format education in that field, but I’ve always understood OFDM MIMO to be slightly more efficient than MIMO applied to other technologies.
3) Very small point semi-related I forgot to give in my last post: 802.11n single-antenna benefits from transmit diversity, just like cellular has for so long. So that obviously increases efficiency further.